The purpose of this study was to determine whether a cyclic adenosine 3',5'monophosphate-dependent process can be involved in the regulation of vascular smooth muscle ai-adrenergic receptor responsiveness. Experiments were performed in cultured rabbit aortic smooth muscle cells which were characterized previously according to a-adrenergic receptorbinding characteristics and receptor-coupled nor...

BACKGROUND Peripheral vascular disease in pre-diabetes may involve altered sympathetically-mediated vascular control. Thus, we investigated if pre-diabetes modifies baseline sympathetic Y(1)-receptor (Y(1)R) and α(1)-receptor (α(1)R) control of hindlimb blood flow (Q(fem)) and vascular conductance (VC). METHODS Q(fem) and VC were measured in pre-diabetic ZDF rats (PD) and lean controls (CTRL)...

The alpha-1L adrenoceptor (AR) was identified in rabbit ear artery by both functional and ligand binding studies. In functional studies using arterial rings, the contractile response to NS-49 [(R)-(-)-3'-(2-amino-1-hydroxyethyl)-4'-fluorometh-anesulfonanilide hydrochloride] (alpha-1A and alpha-1L AR-selective agonist) was competitively antagonized with low affinities by prazosin, RS-17053 [N-[2...

We investigated the role of alpha-adrenergic antagonists and clonidine injected into the medial septal area (MSA) on water intake and the decrease in Na+, K+ and urine elicited by ANGII injection into the third ventricle (3rdV). Male Holtzman rats with stainless steel cannulas implanted into the 3rdV and MSA were used. ANGII (12 nmol/ micro l) increased water intake (12.5 +/- 1.7 ml/120 min). C...

In the dog saphenous vein (DSV), phenylephrine (PE) responses through alpha-1 adrenoceptors receptors are antagonized by both alpha-1 and alpha-2 receptor antagonists. Furthermore, pretreatment with chloroethylclonidine (CEC) eliminates prazosin binding but reduces rauwolscine binding by half (). In new functional experiments, the effects of preincubation with phenoxybenzamine (PBZ), an irrever...

The effects of different alpha-1 adrenoceptor blockers on the urethra and the cardiovascular system were evaluated using an in vivo isovolumetric intra-urethral pressure model in New Zealand white rabbits. The urethra of anesthetized male rabbits was cannulated through the bladder and secured at the vesico-urethral junction. The distal side of urethra under the pubic bone was also closed to all...

An azide analog, 2-[4-(4-azidobenzoyl)piperazin-1-yl]-4-amino-6, 7-dimethoxyquinazoline (CP59,430), of the highly selective alpha 1-adrenergic receptor antagonist prazosin was synthesized and its effects on rat hepatic membrane and affinity-purified alpha 1-adrenergic receptor preparations were examined. CP59,430 behaved as a competitive antagonist before photolysis. When the membrane or purifi...